Gas turbine engine fuel conveying member

ABSTRACT

A fuel conveying member for a gas turbine engine, the fuel conveying member including a fuel manifold having a plurality of fuel nozzles extending therefrom. The fuel manifold is mounted within the engine by a support system, including integral attachment lugs on the fuel manifold for mounting the fuel manifold within the gas turbine engine. The attachment lugs re adapted to receive pins therein and provide a mounting mechanism which allows for thermal expansion of the fuel manifold relative to a surrounding support structure to which the fuel manifold is mounted via the attachment lugs.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 12/209,730 filed Sep. 12, 2008, which was a continuation of U.S.patent application Ser. No. 11/034,838 filed Jan. 14, 2005, nowabandoned, the entire content of each of which is incorporated herein byreference.

TECHNICAL FIELD

The invention relates generally to a fuel conveying member in a gasturbine engine.

BACKGROUND OF THE ART

Fuel conveying passages, conduits, manifolds and the like employed ingas turbine engines tend to gradually accumulate a build up of carbon orcoke. Cleaning fuel passages requires chemical solvents or pyrolysis(heating and pressurizing with air). While such pyrolytic cleaningprocesses are generally effective they are often not easilyaccomplished. U.S. Pat. No. 4,377,420 to Granatek et al. discloses anapparatus which is quite large and expensive. Further, in order to heatup a relatively large component, such as the intermediate turbine case20 depicted by Granatek et al. for example, the enclosed furnace 34 mustbe large.

Accordingly, there is a need to provide an improved fuel conveyingmember of a gas turbine engine.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an improved gas turbineengine fuel conveying member.

In one aspect, there is provided a fuel conveying member of a gasturbine engine comprising a fuel manifold defining an annular fuel flowpassage through a body of the fuel manifold, the manifold having aplurality of fuel nozzles extending therefrom in fluid flowcommunication with said annular fuel flow passage, the fuel manifoldincluding integral attachment lugs thereon for mounting the fuelmanifold within the gas turbine engine, the attachment lugs beingadapted to receive pins therein and providing a mounting mechanism whichallows for thermal expansion of the fuel manifold relative to asurrounding support structure to which the fuel manifold is mounted viathe attachment lugs.

There is also provided a gas turbine engine including a compressor, acombustor and a turbine, comprising: a fuel manifold defining an annularfuel flow passage through a body of the fuel manifold, the body of saidfuel manifold being composed of a first heat conducting material, themanifold having a plurality of fuel nozzles extending therefrom in fluidflow communication with said annular fuel flow passage, the fuelmanifold being supported by a fuel inlet and integral attachment lugsthereon which mount the fuel manifold adjacent the combustor within thegas turbine engine, the integral attachment lugs matingly receivecorresponding pins therein, the pins being engaged to a supportstructure surrounding the fuel manifold, the attachment lugs and themating pins being configured for relative sliding motion therebetweensuch as to provide a mounting mechanism which allows for thermalexpansion of the fuel manifold relative to the surrounding supportstructure at high temperatures.

There is also provided a fuel injection system for a gas turbine engineincluding a compressor, a combustor and a turbine, comprising: anannular internal fuel manifold disposed adjacent the combustor within asurrounding gas generator casing, the fuel manifold having at least onefuel conveying passage therein in fluid flow communication with aplurality of fuel injection nozzles disposed about the fuel manifold andadapted to spray fuel into the combustor; and a mounting systemsupporting and positioning the fuel manifold relative to the combustorwithin said gas generator casing, the mounting system including at leasttwo pin supports circumferentially spaced apart about the annular fuelmanifold, the pin supports including ring lugs and mating pins disposedbetween the fuel manifold and the surrounding gas generator casing, thepins co-operating with the aligned ring lugs such that the ring lugs areslidingly disposed around the pin for relative sliding displacementtherebetween, the pin supports providing axial constraint for the fuelmanifold while permitting radially displacement thereof relative to thesurrounding gas generator casing due to thermal size change.

There is further provided an internal fuel manifold assembly for a gasturbine engine comprising: a fuel manifold ring having at least one fuelconveying passage therein in fluid flow communication with a pluralityof fuel injection nozzles adapted for spraying fuel into a combustor ofthe gas turbine engine; and a mounting system for supporting andpositioning the fuel manifold ring within the gas turbine engine, themounting system including at least one lug disposed on a periphery ofthe fuel manifold ring and a fuel inlet to the annular fuel manifoldbody, the lug having a radially oriented hole therein adapted forslidingly receiving a corresponding radially extending support pintherein.

Further details of these and other aspects of the present invention willbe apparent from the detailed description and figures included below.

DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying figures depicting aspects ofthe present invention, in which:

FIG. 1 is schematic cross-sectional view of a gas turbine engine;

FIG. 2 is a perspective view of a fuel manifold in accordance with thepresent invention, for use in a gas turbine engine such as that depictedin FIG. 1; and

FIG. 3 is a cross-sectional view of the fuel manifold of FIG. 2, takenthrough line 3-3 thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a gas turbine engine 10 of a type preferably providedfor use in subsonic flight, generally comprising in serial flowcommunication a fan 12 through which ambient air is propelled, amultistage compressor 14 for pressurizing the air, a combustor 16 inwhich the compressed air is mixed with fuel and ignited for generatingan annular stream of hot combustion gases, and a turbine section 18 forextracting energy from the combustion gases.

Fuel is injected into the combustor 16 of the gas turbine engine 10 by afuel injection system 20 which is connected in fluid flow communicationwith a fuel source (not shown) and is operable to inject fuel into thecombustor 16 for mixing with the compressed air from the compressor 14and ignition of the resultant mixture. The fan 12, compressor 14,combustor 16, and turbine 18 are preferably all concentric about acommon central longitudinal axis 11 of the gas turbine engine 10.

Referring to FIG. 2, the fuel injection system 20 includes at least onefuel conveying member through which fuel flows. In the exemplaryembodiment, the fuel injection system includes an annular fuel manifoldring 22 which is mounted adjacent to the combustor 16 in the gas turbineengine 10. The fuel manifold ring 22 is preferably mounted to thecombustor 16 or to surrounding support structure via several integralattachment lugs 24 which receive pins (not shown) engaged to the supportstructure. This provides a mounting mechanism which allows for thermalexpansion of the fuel manifold ring 22 at high temperatures. A pluralityof fuel injecting nozzle assemblies 26 are provided about thecircumference of the fuel manifold ring 22. The fuel nozzle assemblies26 atomize the fuel as it is injected into the combustor for ignitionwhen mixed with the compressed air therein. Fuel enters the annular fuelmanifold ring 22 via fuel inlet 30, and is distributed within themanifold ring 22 such that fuel flow is provided to each of the fuelnozzles assemblies. Both the fuel manifold ring 22 and the fuelinjecting nozzle assemblies 26 comprise fuel conveying members, withinwhich a heating device in accordance with the present invention ispreferably provided, as will be discussed in further detail below.

Referring now to FIG. 3, the interior construction of one embodiment ofthe fuel manifold ring 22 and a fuel nozzle assembly 26 of the fuelinjection system 20 is depicted. Particularly, the fuel nozzle assembly26 projects axially (relative to the central longitudinal axis 11 of thegas turbine engine 10) outwardly from fuel manifold ring 22, andincludes a central body 31 from which air swirler vanes 32 project abouta central spray tip opening 33 defined in the central body 31 andthrough which the fuel exits the fuel nozzle assembly 26. An inner fuelnozzle portion 36 defines a central fuel channel 35 therethrough, whichextends between a fuel source passage 40 and the spray tip opening 33.The inner fuel nozzle portion 36 is preferably engaged with thesurrounding central body 31 of the nozzle assembly by a local brazeattachment which provides a seal therebetween. A fuel swirler 34 is alsopreferably provided within the central fuel channel 35 of the inner fuelnozzle portion 36. The fuel flow passage 40 is defined within interiorwalls 41 thereof, and preferably defines an annular passage providedwithin the fuel manifold ring 22, however it is to be understood thatthe fuel flow passage could be provided separately in each fuel nozzleassembly 26 rather than extending throughout a common manifold. However,a common manifold renders the present invention more viable, as only asingle fuel conveying area need be heated, as will be described ingreater detail below. The central body 31 includes a rear body portion38 which projects into the fuel manifold ring 22 and at least partiallydefines the fuel source passage 40 therewithin. A rear sealing plate 42is fastened to the rear walls of the rear body portion 38 at the openend thereof, thereby enclosing the fuel flow passage 40 of the manifold.Preferably, the rear sealing plate 42 is brazed in place about the fullcircumference of the manifold ring. The exterior of the annular fuelmanifold ring 22 comprises an outer heat shield 23 which covers thering. This provides the fuel manifold ring 22 with thermal protectionfrom the high temperature environment of the combustion chamber.

The fuel conveying members such as the fuel nozzles and the fuelmanifold are further provided with at least one heating means such asthe heating device 50 disposed in heat conducting communication with afuel flow passage, such as the manifold fuel passage 40 for example, inat least one of the fuel conveying members such as the fuel nozzles 26and the fuel manifold 22. The heating device 50 is operable to heat upthe fuel flow passages to a temperature which is sufficiently high toallow for pyrolysis of any carbon-based deposits which may haveaccumulated with the fuel flow passages. Such carbon-based deposits caninclude carbon or coke which tends build up on passage walls over timeand eventually partially clog the flow of fuel therethrough. By heatingup the preferably metallic fuel conveying passages to a high enoughtemperature to permit expansion thereof, any adhesion of the carbon andthe wall surfaces of the passage is broken as a result of a thermalgrowth mismatch between the carbon and the metallic wall surfaces, thusloosening the carbon deposits. Thus, the fuel conveying member can be socleaned in situ, using the integral heating device 50, withoutnecessarily requiring complete removal of the entire part for insertioninto a large oven, or the like. Cleaning of the fuel conveying member istherefore possible in situ within the engine, and even “on the wing” ifrequired (i.e. without requiring removal of the engine from theaircraft).

Preferably, once the fuel flow passages of the fuel conveying membershave been heated as described using the integrally provided heatingdevice 50, pressurised air is subsequently fed through the fuel flowpassages. Preferably, the pressurized air is fed into the fuel flowpassages of the fuel manifold via the fuel inlet 30, which isdisconnected from the rest of the fuel system prior to conducting thepresent pyrolytic cleaning process. However, it remains possible tointroduce the pressurized air into the fuel flow passages of theparticularly fuel conveying member via another suitable inlet port. Thepresence of flowing air, and more particularly oxygen in the air, helpsto pyrolize the dislodged carbonaceous deposits, forming generallycarbon monoxide and/or carbon dioxide. Thus pressurized air/oxygenforced through the passages provides a deposit removal means whichfurther improves the pyrolysis of the carbonaceous deposits, as doesenriching the air with oxygen. Although the fuel flow passages can becleaned using only the heating device 50, best results are achieved withpressurized air is also used, reducing the overall time required toperform such a maintenance procedure.

Referring back to FIG. 3 in more detail, the heating device 50 ispreferably integrated within the fuel manifold ring 22, and moreparticularly embedded within the rear sealing plate 42 of the manifoldring. The heating device 50 is preferably contained within a heatconducting capsule 46, composed of a relatively soft conductive materialsuch as aluminum, for example. The capsule 46 is disposed within acorresponding cavity 45 defined within the sealing plate 42, and remainsin direct contact with the sealing plate 42 when disposed in the cavity45. The encapsulation material of capsule 46 provides a substantiallyuniform heat distribution from the heating device 50 as it spreads,largely by conduction, to the rest of the fuel manifold 22 and the fuelnozzle assembly 26. The heating device 50 preferably comprises anelectrical resistance heating element 52, such as an electricallyconductive filament for example, which radiates heat when electricity ispassed therethrough. Other types of integral heating devices can also beused, such as induction, fluidic, pneumatic, etc., however an electricalheating element is preferred for ease of operation. The electricalheating element 52 is preferably led out through the fuel inlet andterminates with electrical connectors or terminals (not shown), suchthat the electrical heating element 52 can be engaged to a suitablepower supply, such as a battery or a DC power supply for example, toenergize the electrical element of the heating device.

When cleaning the fuel flow passages using the heating device 50, anyrubber sealing rings, or any other materials which may degrade by heat,are preferably removed prior to initiating the heating of the fuelpassages by the heating device 50. If such a fuel flow passage cleaningis being performed directly in situ in the engine's operatingenvironment, such as when still installed “on the wing” in the case ofan airborne gas turbine engine, then the fuel inlet would also typicallybe disconnected from the fuel source prior to heating the fuel conveyingmembers. The pressurized air used to help pyrolize the carbonaceousdeposits may be provided by a portable supply or a suitable alternatepressurized air source, which is preferably engaged in fluid flowcommunication with the fuel inlet 30 of the manifold to injectpressurized air into the fuel manifold. It remains possible, however, tointroduce the pressurized air into the fuel flow passage via anothersuitable inlet port.

External insulation is also preferably provided about at least part ofthe fuel conveying members, such that the amount of wasted power isreduced. As such, an insulator is provided about at least the centralbody 31 of the fuel manifold ring 22. Particularly, an insulating aircavity 54 surrounds the rear body walls 38 and the sealing plate 42,within which the fuel flow passage 40 is defined, and within the outerheat shield 23 of the fuel manifold ring 22. Further insulation may alsobe provided outside the heat shield 23, such that most of the heatgenerated by the heating device 50 is directed to the fuel flow passage40 for pyrolysis.

The above description is meant to be exemplary only, and one skilled inthe art will recognize that changes may be made to the embodimentsdescribed without department from the scope of the invention disclosed.For example, alternate configurations of fuel conveying members such asfuel manifolds and fuel nozzles can be used. Further, it is to beunderstood that the heating device could be integrated directly into thewall section without any intermediate material therebetween, or may haveany other suitable configuration. Multiple heating devices may beemployed, of same or different types and configurations. Althoughdescribed with respect to airborne gas turbines, the invention may beapplied to any suitable engine in a suitable application. Still othermodifications which fall within the scope of the present invention willbe apparent to those skilled in the art, in light of a review of thisdisclosure, and such modifications are intended to fall within theappended claims.

1. A fuel conveying member of a gas turbine engine comprising a fuelmanifold defining an annular fuel flow passage through a body of thefuel manifold, the manifold having a plurality of fuel nozzles extendingtherefrom in fluid flow communication with said annular fuel flowpassage, the fuel manifold including integral attachment lugs thereonfor mounting the fuel manifold within the gas turbine engine, theattachment lugs being adapted to receive pins therein and providing amounting mechanism which allows for thermal expansion of the fuelmanifold relative to a surrounding support structure to which the fuelmanifold is mounted via the attachment lugs.
 2. The fuel conveyingmember of claim 1, wherein the attachment lugs comprise an axiallyprojecting flange having a radially extending opening therein.
 3. Thefuel conveying member of claim 2, wherein the openings of said lugs aresubstantially circular in cross-sectional shape.
 4. The fuel conveyingmember of claim 1, wherein the fuel manifold is annular and theattachment lugs include at least two attachment lugs circumferentiallyspaced apart on an outer periphery of the annular fuel manifold.
 5. Thefuel conveying member of claim 4, wherein the fuel manifold includes aradially extending fuel inlet providing fuel flow to the fuel flowpassage, the fuel inlet comprising a third support for said fuelmanifold.
 6. The fuel conveying member of claim 5, wherein the fuelinlet is disposed at a lowermost point of the annular fuel manifold. 7.The fuel conveying member of claim 6, wherein the two attachment lugsand the fuel inlet are circumferentially equally spaced apart about theannular fuel manifold.
 8. The fuel conveying member of claim 1, whereinsaid attachment lugs and said pins mate together to define a support forsaid fuel manifold which provides axial constraint while permittingradial thermal expansion of the fuel manifold.
 9. The fuel conveyingmember of claim 1, wherein the fuel conveying member includes a heatingdevice disposed within a body of said fuel conveying member in heattransfer communication with said fuel flow passage, such that whenactivated said heating device heats said fuel flow passage to atemperature sufficiently high to permit pyrolysis of carbonaceousdeposits in the fuel flow passage.
 10. The fuel conveying member ofclaim 9, wherein the body of said fuel conveying member is composed of afirst heat conducting material, and wherein said heating device includesa heating element embedded in a heat conducting capsule disposed in saidbody of the fuel conveying member, said heat conducting capsule beingcomposed of a second heat conducting material softer than the first heatconducting material of said body thereby providing substantially uniformheat distribution throughout said fuel conveying member.
 11. A gasturbine engine including a compressor, a combustor and a turbine,comprising: a fuel manifold defining an annular fuel flow passagethrough a body of the fuel manifold, the body of said fuel manifoldbeing composed of a first heat conducting material, the manifold havinga plurality of fuel nozzles extending therefrom in fluid flowcommunication with said annular fuel flow passage, the fuel manifoldbeing supported by a fuel inlet and integral attachment lugs thereonwhich mount the fuel manifold adjacent the combustor within the gasturbine engine, the integral attachment lugs matingly receivecorresponding pins therein, the pins being engaged to a supportstructure surrounding the fuel manifold, the attachment lugs and themating pins being configured for relative sliding motion therebetweensuch as to provide a mounting mechanism which allows for thermalexpansion of the fuel manifold relative to the surrounding supportstructure at high temperatures.
 12. The gas turbine engine as defined inclaim 11, wherein the fuel manifold is an annular fuel manifold ring,the attachment lugs include two lugs on the periphery of the fuelmanifold ring, the two lugs and the fuel inlet being equally spacedapart about the circumference of the fuel manifold ring.
 13. The gasturbine engine as defined in claim 12, wherein the fuel inlet isdisposed at a lowermost point of the annular fuel manifold ring.
 14. Thegas turbine engine as defined in claim 13, wherein the two attachmentlugs and the fuel inlet are circumferentially equally spaced apart aboutthe annular fuel manifold ring.
 15. The gas turbine engine as defined inclaim 14, wherein said lugs and said pins mate together to define asupport for said fuel manifold which provides axial constraint whilepermitting radial thermal expansion of the fuel manifold.
 16. The gasturbine engine of claim 11, wherein heating means is disposed withinsaid fuel manifold for heating said annular fuel flow passage to apyrolysis temperature of carbonaceous deposits in said annular fuel flowpassage, said heating means including a heat conducting capsule disposedin said body of the fuel manifold, the heat conducting capsule having aheating element embedded in a second heat conducting material which issofter than the first heat conducting material of said body of the fuelmanifold, thereby providing substantially uniform heat distributionthroughout said fuel manifold.
 17. A fuel injection system for a gasturbine engine including a compressor, a combustor and a turbine,comprising: an annular internal fuel manifold disposed adjacent thecombustor within a surrounding gas generator casing, the fuel manifoldhaving at least one fuel conveying passage therein in fluid flowcommunication with a plurality of fuel injection nozzles disposed aboutthe fuel manifold and adapted to spray fuel into the combustor; and amounting system supporting and positioning the fuel manifold relative tothe combustor within said gas generator casing, the mounting systemincluding at least two pin supports circumferentially spaced apart aboutthe annular fuel manifold, the pin supports including ring lugs andmating pins disposed between the fuel manifold and the surrounding gasgenerator casing, the pins co-operating with the aligned ring lugs suchthat the ring lugs are slidingly disposed around the pin for relativesliding displacement therebetween, the pin supports providing axialconstraint for the fuel manifold while permitting radially displacementthereof relative to the surrounding gas generator casing due to thermalsize change.
 18. The fuel injection system as defined in claim 17,wherein the fuel manifold includes a radially extending fuel inletproviding fuel flow to the fuel conveying passage, the fuel inletcomprising a third support for said fuel manifold.
 19. The fuelinjection system as defined in claim 18, wherein the fuel inlet isdisposed at a lowermost point of the annular fuel manifold.
 20. The fuelinjection system as defined in claim 17, wherein the pins and theco-operating ring lugs of said pin supports are respectively engaged tothe gas generator casing and the fuel manifold.
 21. The fuel injectionsystem as defined in claim 17, wherein the fuel manifold includes aheating device disposed within a body of said fuel manifold in heattransfer communication with said fuel conveying passage, such that whenactivated said heating device heats said fuel conveying passage to atemperature sufficiently high to permit pyrolysis of carbonaceousdeposits in the fuel conveying passage.
 22. The fuel injection system ofclaim 21, wherein the body of said fuel manifold is composed of a firstheat conducting material, and wherein said heating device includes aheating element embedded in a heat conducting capsule disposed in saidbody of the fuel manifold, said heat conducting capsule being composedof a second heat conducting material softer than the first heatconducting material of said body thereby providing substantially uniformheat distribution throughout said fuel conveying member.
 23. An internalfuel manifold assembly for a gas turbine engine comprising: a fuelmanifold ring having at least one fuel conveying passage therein influid flow communication with a plurality of fuel injection nozzlesadapted for spraying fuel into a combustor of the gas turbine engine;and a mounting system for supporting and positioning the fuel manifoldring within the gas turbine engine, the mounting system including atleast one lug disposed on a periphery of the fuel manifold ring and afuel inlet to the annular fuel manifold body, the lug having a radiallyoriented hole therein adapted for slidingly receiving a correspondingradially extending support pin therein.
 24. The internal fuel manifoldassembly as defined in claim 23, wherein the mounting system includestwo lugs on the periphery of the fuel manifold ring, the two lugs andthe fuel inlet being equally spaced apart about the circumference of thefuel manifold ring.
 25. The internal fuel manifold assembly as definedin claim 23, wherein said lug and said support pin mate together todefine a support for said fuel manifold which provides axial constraintwhile permitting radial thermal expansion of the fuel manifold.
 26. Theinternal fuel manifold assembly as defined in claim 23, wherein the fuelmanifold ring includes a heating device disposed within a body of saidfuel manifold ring in heat transfer communication with said fuelconveying passage, such that when activated said heating device heatssaid fuel conveying passage to a temperature sufficiently high to permitpyrolysis of carbonaceous deposits in the fuel conveying passage. 27.The internal fuel manifold assembly as defined in claim 26, wherein thebody of said fuel manifold ring is composed of a first heat conductingmaterial, and wherein said heating device includes a heating elementembedded in a heat conducting capsule disposed in said body of the fuelmanifold, said heat conducting capsule being composed of a second heatconducting material softer than the first heat conducting material ofsaid body thereby providing substantially uniform heat distributionthroughout said fuel conveying member.